Fluid pump with controlled variable flow



eb. 18, 1969 E. r2. comma.

FLUID PUMP WITH CONTROLLED VARIABLE FLOW l of 3 Sheet Filed June 27, 1957 INVENTOR Per.. 1s, 1969 E. n. CRNEIL 3,427,986

FLUID PUMP WITH CONTROLLED VARIABLE FLOW Filed June 27, 1967 sheet 2 of s I INVENTOR Feb. 18, 1969 E. R. coRNEn.

FLUID PUMP WITH CONTROLLED VARIABLE FLOW med .June 27, 1967 Sheet INVENTOR United States Patent O Claims ABSTRACT OF THE DISCLOSURE Fluid pump in which reciprocating, or oscillating members distort a tube, progressively along a length of the tube to produce a fluid flow. The members are reciprocated about a first centre by a cam or similar action, and constrained by a linkage also to reciprocate about a second centre. By varying the position of the second centre, relative to a line through the .irst centre and a point of attachment of the linkage to a member, the displacement of the member, and the degree of distortion of the tube, between fully closed and fully opened, can be controllably varied and thus the flow rate varied, with constant speed.

BACKGROUND OF TH-E INVENTION Field of the invention The present invention relates to fluid pumps of the type in which a flexible tube is progressively distorted to produce a pumping action and is concerned with providing a volumetric iiow control, independent of speed of operation.

Description of the prior art Various forms of pump have been proposed, in which a iiexible tube is distorted to produce the pumping action. Hitherto, the rate of flow has been controlled by varying the frequency of the cycle and this necessitates variable speed drives. With electric and other constant speed power units, some form of variable speed gear has to be interposed between the pump and the power unit. Also, for very small flows, a small bore tube is required, as the iiow rate is also dependent on the tube bore diameter. To provide a wide range of ilow rates, a variety of tubes with diiering bores, and wall thicknesses, are required. To date, no pumps of the distortable tube type are available to provide a controlled variable flow at a constant Speed from a given iiexible tube member.

SUM-MARY The present invention provides a pump, of the liexible tube type, in which the tube is distorted by reciprocating members, in which the extent of reciprocation of the members is controllably variable. The invention also provides, in a modification thereof, means for adjusting the datum of the reciprocating members, to accommodate tubes of differing wall thicknesses.

BRIEF DESORIPTION OF THE DRAWINGS The invention will be understood by the following description of certain embodiments, by way of example, in conjunction with the accompanying drawings, in which:

FIGURE 1 is an external side view of one for-m of apparatus,

FIGURE 2 is a cross-section, on the line 2 2 of FIG- URE 4, with the mechanism at a minimum flow rate position,

FIG-URE 3 is a cross-section similar to that of FfIG- URE 2, but with the mechanism .at a position approaching that for maximum iiow rate, t

FIGURE 4 is a sectional view on the line 4-4 of FIGURE 2,

FIGURE 5 is a cross-section on the line 5-'5 of FIG- 3,427,986 Patented Feb. 18, 1969 'UfR-E 2, through one oscillating member and associated linkage,

FIGURE 6 is a cross-section on the line 6-6 of FIG- IUfRE 3, but with the oscillating members and associated cams and linkages omitted for clarity, illustrating an additional feature of the invention, and

FIGURE 7 is a plan View illustrating the distortion of al tube.

DESCRIPTION OF TI-I-E PREFERRED EMBODIMENTS Considering FIGURES l to 4, the pump comprises a casing, or housing, 10 open at one side and which is closed by a cover plate 11 secured by screws 12. A camshaft 13 is journalled at one end 1-4 in an end wall 15 of the housing 10, and journalled at the other end 16 in the cover plate 11. The cam shaft has a series: of uniform cams 17 thereon and an extension 18 for driving by some suitable power source, not shown. The cams 17 are arranged sequentially along the cam shaft 13, normally with equal relative angular displacement.

Mounted on each of the cams 17 is a reciprocating, or oscillating, member 20. Each member 20 engages its related cam by a yoke 21 formed at one end of the member. A series of rotatable supports 22 are journalled in a bearing mounting 23 in one wall 24 of the housing 10. A Support 22 is provided for each member 20, the mernber slidably retained in a slot 25 in the support.

The cams 17, on rotation of the cam-shaft 13, cause reciprocation, or oscillation, of the members 20, each about the axis of rotation of its related support 22. The cams do not directly cause movement of the members 20 in a direction parallel to their longitudinal axis, although the yokes 21 permit such movement of the members 20.

A boss 26 is formed on one side of the yoke 21 on each member 20. The bosses 26 provide pivotal attachment points for one end of links, or levers, 27. The other end of each link 27 is pivotally journalled on a shaft 30. The shaft 30 extends parallel to the axis of rotation of the supports 22 and also to an axis passing through the points of attachment of the links 27 to the members 20. The shaft 30 is supported in the housin-g 10 by two parallel, spaced apart, levers in the form of seg-ments 31. The segments are each pivotally mounted at an apex 32 and the shaft 30` is attached at one end o-f the arcuate surface 33 of each segment by screws 3-4. The :arcuate surfaces 33 of the segments are formed to provide arcuate rack lgears which mesh with a gear pinion 35 extending across the housing, the gear being rotatably supported in bearings 36 and 37 in the end wall 15 and the cover 11. One end of the gear 35 is extended as a shaft 38 for attachment of a control dial 39.

It will be seen that rotation of the gear 35, by the control dial 39, will rotate the segments about their pivotal mountings at their apices 32. Movement of the segments will vary the position of the shaft 30 relative to the axis of rotation of the supports 22 and the axis through the pivotal attachment points of the links 27 to the members 20.

In operation, cam-shaft 13 is rotated, rotating the cams 17. Rotation of the cams reciprocates, or oscillates, members 20 about the rotational axis of the supports 22. Considering the member 20` and link 27, as shown in EIG- U'RE 2, as the member 20 oscillates about the rotational axis of support 22, the link 27 also oscillates about the axis of shaft 30. The relative position of the link and member, in FIGURE 2, is the one `giving substantially minimum ilow. The axis of shaft 30 is in line with the axis of support 22 and the axis of the point of attachment of the link 27 with the boss 26. In such a position very little movement of the member 20 along its longitudinal axis occurs.

To produce movement of the members 20, along their longitudinal axes, the gear 35 is rotated by the dial 39. 'I'his -moves the axis of the shaft 30 out of alignment with the axis of the supports 22 and the points of attachment of the links to the bosses. One such position of shaft 30 is shown in FIGURE 3, the shaft approaching the maximum out of line displacement, 1f now the movements of a member and link 27 is considered, it will be seen that as camshaft 13 rotates, cam 17 will oscillate member 20 about the rotational ax-is of the support 22. Link 27 will be oscillated about shaft 30. However, with shaft displaced out of line with the axis of support 22 and axis of the attachment of the link 27 with boss 26, two components of movement will be imposed on the boss 26, one normal to a line connecting the rotational axes of camshaft 13 and support 22 and the other along that line. Thus the member 20 will be reciprocated along its length. The position of member 20 on 180 rotation of the cam 17 -is shown in phantom at 42.

Each support 22 is provided with a flat surface 43 and each member 20 is provided with a lateral extension 44 at its end remote from the yoke 21. Each extension 44 has a at surface which faces toward the flat surface 43 on the related support 22. Reciprocation of a member 20 along its length varies the gap between the opposed flat surfaces 43 and 45.

A flexible tube 50, FIGURES l and 7, is positioned between the flat surfaces 43, 45, and reciprocation of the members 20 distorts the tube. With the cams 17 equally angularly displaced on the camshaft 13 a regular wave will travel along the tube progressively distorting the tube to provide a pumping action.

With the position of shaft 30 in FIGURE 2 giving the minimum 4movement of the member 20 along its longitudinal axis, this represents the minimum pum-ping action and minimum flow. The position of the shaft 30 as shown in FIGURE 3 is nearly at the maximum displacement and giving nearly maximum movement of member 20 along its longitudinal axis, with corresponding nearly maximum pumping action and flow. Variation of the positioning of the shaft 30, intermediate the two positions shown in FIGURES 2 and 3, will give variation in pumping action and flow. This variation of the position of shaft 30 is obtained by rotation of the control dial 39. Suitable indents 47, formed in the periphery of the dial 39, and cooperating with a spring-loaded pin 48, or some similar device, provide a convenient way of varying the pumping action, and ow rate by predetermined steps.

Although only the movement of one member 20 and associated link 27 has been described in detail, the movements of all members 20 and associated links 27 are the same. To provide reasonable bearing surfaces for the members 20, each yoke is flanged at 51. The links 27 are positioned between the members 20, in the spaces provided by the flanges 51. FIGURE 5 illustrates the position of one member 20` and its link 27.

Thus, considering FIGURES 1 to 5, it will be seen that rotation of the camshaft 13 will cause a travelling wave to move along the tube 50, progressively distorting it and then allowing it to return to its undistorted shape. By manipulation of the control dial 39, the amplitude of the wave can be controllably varied from substantially zero to a maximum. At the zero condition the tube is distorted into a closed condition and remains so distorted. Movement of the control dial 39 a small amount will result in `some small amount of reciprocation of members 20, the tube being completely occluded at one spot only at any given point of rotation, the rest of the tube being slightly open. At the maximum condition, the tube will be completely occluded at the one position, which can be considered as the trough of the wave, and will be increasingly opened up to a position which can `be considered as corresponding to the peak of the wave, giving maximum flow. Normally, in the maximum condition, the tube will be completely open, i.e., undistorted at the 4- position considered as the peak of the wave However, this is not a necessity, and there may always be some distortion of the tube 50'. No variation in speed of rotation of the camshaft 13 is required for this Variation in flow.

It is desirable that some adjustment be available to permit initial adjustment of the gap -between the opposed flat surfaces 43 and 45. The thickness of the wall of tube 50 is likely to vary from tube to tube. It is necessary to completely occlude the tube for maximum pumping activity but at the same time it is desirable to avoid overcompressing the tube to avoid damage.

An additional, optional, feature of the apparatus is the provision of means for adjusting the gap between surfaces 43 and 45, independently of the cams 17, members 20 and links 27. As stated above, the segments 31 are pivotally mounted at their apices 32. As seen more clearly in FIGURE 6, the segments 31 are pivotally mounted by rivets 55 on an adjustable yoke member 56. The yoke member is pivotally mounted, at the ends of legs 57, at the position at which the gear 35 is supported in the end wall 15 and the end cover 11. Conveniently, the ends of the legs 57 form the bearings 36 and 37 which support the gear 35. By this arrangement, the yoke member 56 can rotationally oscillate about the axis through bearings 36 and 37. This also means that the position of attachment of the segments 31 to the yoke member 56 can also rotationally oscillate about the axis through bearings 36 and 37.

Movement of the yoke will alter the angular position of the segments relative to the members 20 and links 27. Further, as the segments are also pivotally connected to the shaft 30, to which all the links 27 are pivotally connected, the geometry of the relationship between members 20, links 27, segments 31 and gear 35 will vary with alterat-ion of the angular relationship of the segments.

From a mid-position, the yoke member 56 can be rotated clockwise or anticlockwise. Movement of the yoke member 56 is obtained by a control screw 58 rotatably secured in a boss 59 formed on the housing 10 by a screw 60. The control screw has a threaded portion 61 at its inner end which engages with a threaded hole in the yoke member 56. The arrangement is seen clearly in FIGURE 2, the yoke member 56 being at one extreme position of adjustment.

If the control screw 58 is rotated to cause the threaded portion 61 to move yoke 56 anticlockwise as seen in FIGURE 2, then the segments 31 will also be rotated anticlockwise about an axis through the bearings 36 and 37, and through the gear 35. This movement of the segments will move shaft 30 anticlockwise about the axis through bearings 36 and 37. This movement of the shaft 30 will cause the links 27 to move slightly to the right, as seen in FIGURE 2, and will also cause the members 20 to slide slightly to the right, increasing the distance between surfaces 43 and 45. Thus the control screw 58 will enable the datum gap betweenfsurfaces 43 and 45 to be varied. This variation is made without any substantial variation in the operational strokes of the members 20, which is governed by the gear 35 and the segments 31.

From the above it will be seen that the invention provides for a variable flow rate, independent of Speed. Also, if desired, adjustment can readily be provided to adapt for differing thickness of tube wall and similar variations.

I claim:

1. A pump for fluids, comprising; a housing; a series of members mounted in said housing for reciprocal and oscillatory rotative movement in a series of parallel planes; support means supporting said members towards one end for reciprocation and for oscillatory rotation about a rst axis, normal to said planes; a first surface on each of the members, extending transverse to said plane; a series of second surfaces, one opposed to each said first surfaces to cooperate therewith; means adjacent the other ends of said members for sequentially oscillating said members about said rst axis; a series of links extending parallel to said planes, a link to each member; each link pivotally attached at one end to a related member adjacent said other end of said member, said links pivotable relative to the members about a second axis parallel to said first axis; means pivotally connecting the links at their rother ends for pivoting movement about a third axis, positioned between said first and second axes and parallel thereto; and means for varying the position of said third axis relative to a plane parallel to and passing through said rst and second axes and thus varying the pivotal position of said other ends of said links; whereby oscillation of said other ends of said members pivots said links about said third axis to impart a reciprocal movement to said members, the extent of said reciprocal movement increasing with increase in displacement of said third axis; reciprocation of said members varying the distance between said iirst and second surfaces for distortion of a exible tube positioned therebetween to produce a pumping action.

2. Apparatus as claimed in claim 1 wherein the means pivotally connecting the links at their other ends comprises a shaft, the longitudinal axis of the shaft comprising said third axis.

3. Apparatus as claimed in claim 2, wherein said means for varying the position of said third axis comprises at least one lever, said shaft mounted at one end of the lever, the other end of said lever pivotally mounted in said housing for rotative movement in a plane parallel to the planes of movement of said members, and means for moving said lever about said axis.

4. Apparatus as claimed in claim 2, said means for varying the position of said third axis comprising; a pair of segmental levers pivotally mounted at their apices in said housing, movable in planes parallel to said planes of movement of said members, said shaft mounted at an end of the segmental levers remote from said apices, a peripheral arcuate surface at said end of each segmental lever; an arcuate rack ygear formed on each of said arcuate surfaces; a pinion gear pivotally mounted in said housing, having an axis of rotation normal to the planes of movement of said segmental levers, said gear meshing with said arcuate rack gears; and means for controllably rotating said gear.

5. Apparatus as claimed in claim 1, wherein the support means supporting said members comprises a series of support members rotatably mounted in a wall of said housing, a support member for each of said members, said second surfaces comprising surfaces on said support members, one surface on each support member.

6. Apparatus as claimed in claim 1,. wherein said means for sequentially oscillating said members comprises; a cam shaft; and a series of cams on said shaft, sequentially angularly displaced, a cam for each said member.

7. Apparatus as claimed in claim 4, wherein the means for controllably rotating said gear comprises a control dial, rotatable to any one of a series of predetermined positions, and a spring loaded pin adapted for engagement with said dial.

8. Apparatus as claimed in claim 4, wherein said segmental levers are pivotally mounted at their apices in an adjustable member, said adjustable member supported in said housing for pivotal movement about the axis of rotation of said pinion gear, and including means for pivoting said segmental levers about the axis of said pinion gear, whereby the position of the pivotal axis of said segmental levers and the datum position of the third axis relative to the first and second axes can be varied.

9. Apparatus as claimed in claim 8 wherein said adjustable member comprises a yoke member having parallel spaced apart legs, said yoke memberl including bearings at the ends of the legs for pivotal mounting of the yoke member in said housing, said bearings also providing the pivotal mounting for said pinion gear.

10. Apparatus as claimed in claim 9 wherein the means for pivoting said segmental levers comprises a control screw retained in said housing, said screw including a threaded portion engaging in a cooperating threaded hole in said yoke member.

References Cited UNITED STATES PATENTS 1,922,196 8/1933 Butler 103-148 2,105,200 1/1938 Phelps 103-149 2,877,714 3/1959 Sorg etal 103--149 2,922,379 1/1960 Schultz 103-148 3,083,647 4/1963 Muller 103-148 3,128,716 4/1964 Stallman et al 103--149 DONLEY' I. STOCKING, Primary Examiner. WILBUR J. GOODLIN, Assistant Examiner. 

